Friman kahrs



(No Model.)

F. KAHRS. PROCESS OF DISSOLVING' GLUB'AND MAKING CLAY SIZE.

No. 593,845. Patented Nov. 16, 1897.

Z rfi1 amen/{1oz wibmo/aaw I M15578 UNITED STATES PATENT .OFFICE.

FRIMAN KAHRS, OF NEW YORK, N. Y.

PROCESS OF DISSOLVING GLUE AND MAKING CLAY SIZE.

SPECIFICATION forming part of Letters Patent No. 593,845, dated November 16, 1897. Application filed Februaryt, 1897. Serial No. 622,200. (No sp imens) To aZZ whom it may concern:

Be it known that I, FRIMAN KAHRS, a citizen of the United States, residingin New York, in the county and State of New York,

have invented certain new and useful Improvements in Processes of Dissolving Glue and for the Manufacture of Clay Size, a mixture of clay, water, and glue, of which the following is a specification.

This invention relates to improvements in processes for dissolving glue and for the making of clay size; and its object is to expedite the dissolving process and to insure the production of a glue solution and of clay size of improved quality, to do this more rapidly, with less power, and at a lower cost than heretofore. g

The following is a detailed description of the experiments. leading to the invention of the two processes and a separate explanation of each of them under heading A for the dissolving of glue and under heading B for the making of glue size. Under heading A will be found the description of some of the preceding experiments.

A. The dissolving of gZue.-In dissolving glue it is usual first to soak the glue in cold Water, the glue taking up a certain amount of it and swelling to a jelly, which is then melted in a glue-pot. When melted, it is boiled in order to make it fit for use, as the popular notion is that the glue will not yield full strength Without boiling. The soaking. is deemed necessary, because experience shows that hard glue dissolves very slowly in hot or boiling water, as it forms tough sticky lumps that resist reduction; but, on the other hand, it was found that if the glue had been steeped in cold water and had absorbed some of it the melting of the jelly was always comparativel y easy; therefore the soaking. This experience in regard to soaking and the popular belief as to the boiling are both so stronglyimbued by all glue consumers that it was only after repeated demonstrations of the waste of time by soaking and the evident damage done b'yboiling that I found it necessary to inquire into the real facts bysuitable experiments in order to discover the truth, and this is what I found: First, thirty gallons of Water heated in a water-bath could be brought up to 210 Fahrenheit intwenty-five minutes,

cent. glue solution in the shape of a stiff jelly required from ninety to one hundred and twenty minutes for the same result. Second, one pound of steam would heat one thousand five hundred and forty pounds of water 1 Fahrenheit, but the same amount of steam would only heat four hundred and seventyfive pounds of a mixture of water and glue, (and some clay.) It was clear then that glue and glue solutions were poor transmitters of heat and that this caused the delay in heating. Third,experiments with glue jellies had shown that the stiffness of the jelly deoreased'the nearer the temperature rose to the congealingpoint, also that if the temperature exceeded this point by only a few degrees the jelly became liquid, also that nearly all glue solutions had a congealing-point below 95 Fahrenheit. Fourth, while using very warm glue solutions, say above 160 Fahrenheit, it was found that hard glue put in such solutions became soft and very sticky and hard to dissolve. Fifth, examination of glue pieces that by soaking in cold water had become jellified showed the water to have been absorbed gradually toward the center, indicating that the hygroscopic qualities of the glue had been assisted in the water-absorbing act by a certain naturalporosity of the glue while cold. Sixth, this porosity of the hard cold glue changed into stickiness and did not disappear before the.

heat began to soften the glue itself, and this softening changes gradually into stickiness as the temperature of the glue solution increases. Seventh, the softness of the very warm glue had evidently changed the porous condition of the cold glue, and by closing the pores and increasing the natural adhesiveness by increase of temperature induced a stronger cohesion and caused the delay in dissolving the hard glue in the hot glue solution or in hot water. Eighth, if a temperature slightly above the congealing-point of the liquid was used for melting the glue, there was no jelly formation and no stickiness or clogging of the glue particles and the dissolving process went on rapidly and evenly, especially if the denser parts of the solution and the still unmelted glue were by stirring prevented from sinking or settling at the bottom.

Ninth, practical trials proved that thirty gallens of a thirty-per-cent. glue solution could be prepared in twenty-five minutes if kept at a heat not over 120 Fahrenheit and if stirred while dissolving. Tenth, as this was an unboiled solution and as it might not be considered as strong as a boiled solution, a test was made with some of it boiled and some unboiled, both worked into test-pieces alongside of each other. The unboiled glue was stronger by twenty per cent, proving this to be the amount of damage done to the glue by boiling. Eleventh,the practical strength trial had here confirmed what the soaking of glue in water had indicated namely, that glue immersed in cold water absorbs same perfectly and forms a jelly, indicating that glue and water will mix or unite mechanically very well without the use of heat and that a perfeet union of glue and water might be possible without any heat at all without forming a solution. Twelfth, all this had been repeatedly indicated by my experiments, but had never been acted on, as it was absolutely against popular belief and as it lacked the confirmation of practical trials.

I was thus convinced that it was not alone desirable, but even necessary, to abandon the fallacious notions of soaking and boiling glue and reshape the dissolving process on the basis of indications given by the abovenoted experiments. In order to prevent any possible damage done to glue by heat or, heating, I have devised the following process, where I have used to advantage the better understanding of the physical phenomena relating to the dissolving of glue in water, as acquired through the knowledge gained from the experiments described. Glue itself is, as before stated, a very poor conductor of heat, and so are glue solutions in jelly form, as they prevent the convecting currents that always promote the heating of liquids. The best way is therefore to take advantage of the superior heat-absorbin g qualities of water by. heating it to the proper temperature before the glue is added, then to add the glue, taking care not to apply any heat to the mixture after the glue is added, and these are the substantial features of the new process. This process was tried and worked very well, indeed, because when glue is put into lukewarm water the heat is applied to all parts of the glue at once, jellification is prevented, the formation of sticky lumps is impossible, and the dissolving action is comparatively rapid. I find, however, that to give uniform and good results and to increase the rapidity of solution it is better to stir or agitate the mixture after the glue is added to the warm water, first, because this removes the viscous glue solution from the surface of the glue particles as fast as it is formed, thereby exposing continuously new portions of the hard glue to action of the surrounding watery liquid, and, secondly, because otherwise the heavier. glue particles and glue solution would sink to the bottom and remain there. For

reasons formerly stated the temperature of the water at the start must be high enough to raise the final mixture of glue and water above its congealing-point when dissolved; but this temperature must not be high enough to materially soften the hard glue. From to 120 Fahrenheit I have found most suitable for low-grade glues.

Over the old process of melting glue the new one has the following advantages: First, the preparation is done more rapidly. Thirty gallons of a thirty to forty per cent. solution can be dissolved in one-third or one-fourth the time formerly required. Second, the spoiling of the glue by overheating or boiling is done away with entirely. The damage now done by using steam or hot water to heat glue is often very large, especially if it is at- .tempted to hasten the action, and sometimes the value of glue solutions have been reduced by fifty per cent. or more. Third, special advantages arise from the use of this method for the purpose of making clay size, as hereinafter described.

B. The making of clay sizehen making clay size, which is a mixture of water, clay, and glue, the usual method is to mix cold water and cold clay. This is beaten into a stiff dough. Then a warm glue solution is added, and it is beaten again, and then the mixture is thinned out with cold water until proper consistency. This method has many drawbacks. First, it requires a great deal of power as the mixture is rather thick; second, it takes a long time to beat the heavy dough and then to beat the glue into the dough, and again to beat it while finally reducing it; third, it requires an extra and separate preparation of the glue solution; fourth, special separate appliances for the heating of the glue and the beating of the clay; fifth, the warm glue solution of .a rather heavy consistency-thirty to forty-five per cent. is, at the expenditure of much time and power attempted, forced into a cold clay mixture, the temperature of which tends to congeal the glue solution, as this latter only amounts to one-fifth or less of the whole bulk; sixth, this congealing of course retards the mixing; and, seventh, it impairs the adhesiveness of the glue solution, thus frustrating the very object of its presence-namely, the surrounding and permeating of all clay particles by a thin glue solution that will cause and promote cohesion and adhesion to each other and to such surfaces as the mixture may be applied to; eighth, it is nearly impossible to distribute evenly a half-congealed heavy glue solution in a heavy clay dough, as the rat-her heavy liquid only imperfectly enters into the porous clay particles.

By applying my new process of dissolving glue and the method pursued in my process to the mixing and making of clay size the drawbacks of the old method are done away with and the whole matter is greatly simplified. This is how it is done: First, I dissolve the glue in all the water needed to make the whole batch and according to the process before described; second,this is done right in the same mill where the clay mixture is beaten up; third, when the thin lukewarm glue solution is ready I add thereto the necessary amount of clay, and have then in a short time the whole mixture ready, and the preparation is done under circumstances which make sure of full efficiency of the glue used, because glue has none or but little adhesiveness or spreading power if cold.

The mixing of clay size by this process gives from the start all the conditions needed for a perfect result if the ingredients are mixed in this order: water, glue, and clay; but to be sure of a good result the following must be observed: First, the glue solution must be so warm that the 'finalmixture of clay, glue, and water is somewhat warmer than' the congealing-point of the glue solution itself; second, the best results will be obtained with a final mixture at a temperature between and Fahrenheit; third, the glue must be well beaten and all of it dissolved before the clay is added.

Theadvantages of the new process are:

First. Great saving of time and power in making the clay size. Formerly a thick clay dough was beaten with a heavy glue soup and it took long beating for both mixings and hours to melt the glue size. Now all can be done in less than two hours. I

Second. Absolute efliciency of all the glue contained in the mixtu re,as cold clay is beaten up in a thin lukewarm glue solution of such a temperature that all of the complete mixture will be above the congealing-point of the glue solution itself. This is necessary to produce full spreading and adhesiveness. Then every clay particle is from the start embedded in,su rrounded by, and saturated with a glue solutionin such a physical condition that it-possesses its full adhesiveness. The clay particles will then make a uniform and homogeneous mixture with the water and glue. The glue will be evenly distributed throughout the entire mass, and if such a mixture is ap-' plied to any surface in the proper way it will adhere and each clay particle will be united to other particles and to the surface by an evenly-distributed minute glue film. It is obvious that such results cannot be obtained when a heavy glue solution is beaten up with a heavy cold clay dough and the glue itself is too cold to be adhesive and to be spread out.

Third. A saving of glue, as less glue will do better work than formerly.

Fourth, As the process is done in the same vessel from start to finish, the use of separate glue-pots or glue-heaters is done away with and the time, labor, and heat spent on such an appliance are saved.

For a better understanding of the process I refer to the accompanying drawing, which represents a vertical section of a mixing or stirring apparatus adapted to the carrying out both of the dissolving of glue and the mixing of clay size.

A is a vessel or tank in which is mounted a mixing or stirring device consisting of a shaft B, driven by any suitable means, as by a driving-wheel O, and having projecting arms or blades D, which cooperate with fixed blades E, supported from the sides of the tank. Said shaft is provided with abearing B at the bottom of the tank and journaled in a suitable bearing B at the top.

F is a nozzle or pipe connecting with a source of live steam.

In making a glue solution the amount of water necessary to form a batch of liquid glue is put into the tank A, and the steam is then admitted through the pipe F until the water is warmed to the proper degree, or until it is lukewarm, but not so hot that the hand cannot bear it. The temperature to which the water is heated depends to some extent on the amount of glue or glue and clay that is to be added, but it must be sufficiently high to give to the final mixture'a temperature somewhat above the congealing-point of the glue solution itself, while not high enough to cause any lumpiness or sticking together of the dry glue particles, due to excessive softening of,

Fahrenheit are the limits for ordinary condi- Fahrenheit may bring the final temperature below the congealing-pointof the glue solution and then prevent a'perfect mixture to be formed and prevent adhesion of the glue.

The water having thus been brought to the desired temperature the steam-supply is out off and the necessary amount of glue, preferably in a finely-divided condition, is introduced into the tank. The mixer is then set in motion and the particles of glue are quickly dissolved, since the agitation brings each glue particle into continuous contact with a larger quantity of Water than would otherwise be possible, this because the rubbing of the particles against eachv other and against the liquid detaches the viscous melting-surface therefrom as fast as formed and hastens the melting and the dissolving by continuous exposure of more surface on the particles to the dissolving action. By taking advantage of the superior heat-absorbing qualities of water and by imparting all the necessary heat to the Water beforehand I obtain a rapid and uniform heating of the resulting mixture of glue and Water, while there is absolutely no possibility of damage done to the glue by overheating, since no heat is supplied to the mixture after the glue is added. A lumpy of power to stir it.

coagulation of the glue particles is at the same time completely prevented, for while the temperature is above the setting-point of the glue solution it is too low to cause softening and clogging up of the glue itself- The result is a smooth and uniform and perfectly liquid glue solution obtained with a minimum of heat and at the expense of a short time and a little power.

To make clay size, I begin with the making of the requisite quantity of glue solution by dissolving all the glue needed for the batch in all the water needed for the whole batch and in the manner just described. \Vhen all the glue is dissolved and while the watery glue solution is lukewarm, I add to it the necessary quantity of dry clay, which is then by continued beating thoroughly incorporated with the glue solution. In a short time and with but little power the mixture becomes uniform and homogeneous and ready for use. Such clay mixture as now prepared by the usual process is generally of a very thick consistency. The usual way, requiring the mixing of cold clay and cold water before adding the warm glue, gave a clay mixture so thick and doughy as, to require a great deal The watery glue solution made by my process is very easy to stir, and the addition of the clay while thickening it does not by far bring it up to the consistency of the clay water mixture of the old process. Of course the stiifness of the final product is the same, but by my process I start with a liquid very much thinner than the final product and thicken it somewhat toward the close, whereas the old process starts with a mixture thicker than the final product, beats this all the time, and thins it down at the close. The effect of this on the amount of power consumed in mixing is of course considerable; but the main improvement is derived from the new way of handling the glue and the resulting thin glue size and from the mixing of the clay with a watery glue solution of such temperature that the glue will do its work because evenly distributed throughout the entire mass and in the shortest time possible.

' It is a fact that by the new process the mixing of clay size can be done in less time, with less power, and with less glue, thus giving a threefold saving in the cost of the product, and it is also a fact that the resultant product itself is a better one than heretofore made. Some of these advantages may be due to the observation of special physical conditions, some to the different order in which the ingredients are mixed in my process-viz. water and glue first and then clay-as against the usual order-water and clay first, then glueand to the combination of bothspecial conditions and the revised order.

It has now been above proven that the combined knowledge acquired through the experiments described gives, when applied practically, a rapid and economical method that is thoroughly reliable.

I would call especial attention to the fact that this improved process is especially adapted for use with low-grade glues, and in'using such glues it will be necessary to work toward the lower limit of the temperature range I have specified. The process is, in fact, essentially a low'temperature process, and the special advantage thereof is that it enables me to work at a comparatively low temperature, say not above 120 Fahrenheit when working with low-grade glues, and as the amount of heat such glues will stand without coagulation is correspondingly low my process is peculiarly adapted for use with low-grade glues for three reasons-namely, first, solutions made with low-grade glues set at a comparatively low temperature, so that this process which enables me to work down to any temperature not lower than 90 Fahrenheit is especially applicable; second, low-grade glues will stand comparatively little heat, so that the. use of a temperature not above 120 Fahrenheit is necessary; third, low-grade glues are on account of their cheapness the only ones to which a process of this nature, involving for its economical operation the handling of large quantities, is generally applicable.

My invention is also applicable to the manufacture of mixtures of insoluble solid material other than clay with glue solution. Thus calcimine may be made with advantage in a similar manner by first forming a warm solution of glue by the above method and then adding thereto the paris-white and beating up the mixture until thoroughly incorporated.

Having thus described my invention, what I claim as new, and desire to secure by Letters Patent, is-

1. The process of dissolving glue which consists in heating the requisite quantity of water to a temperature above the congealing-point of the glue that is about 00 Fahrenheit and below its softening-point, that is about 120 Fahrenheit and adding the glue to the warm water and incorporating the same therewith, while the solution remains between such limits of temperature.

2. The process of dissolving glue which consists in heating the requisite quantity of water to a temperature sufficient to bring the temperature of the final mixture above the congealing-point of the glue solution, but below the softening-point of the glue itself that is from 90 Fahrenheit to 120 Fahrenheit, then discontinuing the supply of heat, adding the glue, and mechanically stirring the mixture of glue and warm water.

3. The process of making clay size which consists in heating the requisite quantity of water to a temperature suffieient to bring the final mixture to a temperature above the setting-point of such mixture and below the softening-point of the glue, then discontinuing the supply of heat, adding and incorporating the necessary quantity of glue, and finally adding and incorporating the requisite limits of temperature and finally adding and 10 incorporating the requisite amount of solid filling material in a dry absorbent state, substantially as set forth.

FRIMAN KAHRS.

Witnesses:

' HERBERT KNIGHT,

M. V. BIDGOOD. 

